The preparation of hides and skins for tanning or preservation is an art-science that has taken place many years ago and it can be said to be the oldest of industries. In ancient times man used to cover his body with hides and skins which he elementarily prepared by skinning animals and fleshing the skins with primitive instruments. Man soon learned to salt skins to make them contract and give them an adequate consistency for wearing.
As time passed, preparation, tanning and softening technics for hides and skins got more perfected, basically by chemical means and better processes as well as more efficient equipment and control methods that made involved operations in said art-science much easier.
At present, different technics for preparing hides and skins for tanning and further preservation are used, based fundamentally in treating hides and skins with salt or chemical agents such as calcium hydroxide and sodium sulphide, getting more or less satisfactory results. Nevertheless, present processes are comparatively expensive if it is taken into consideration that chemical agents used for preparing hides and skins, once used, are thrown away, which involves environmental contamination, particularly sewages and consequently water currents in which chemical and organic waste residues are carried.
Previous problems have made it necessary to provide an economical and efficient process that do not contaminate the environment, and the process of the present invention surprisingly solves such problems.
Now, it has been discovered that preparation of hides and skins in adequate conditions, produce recoverable solid values that can be used in different industries such as fertilizers feeding, pharmaceutical and biochemical industries and others, due to the excelent properties of such solid values which find a wide field of industrial application.
Besides, the solid values recovered from hides and skins through the process provided by the present invention, chemical agents are saved as treatment baths from hides and skins are practically used indefinitely with a very small expense of chemical agents. In consequence, environmental contamination is eliminated and gases, such as sulphydric acid are recuperated.